Automatic fuel feeding apparatus



Dec. 8, 1931. zfnouKA 1,835,090

AUTOMATIC FUEL FEEDING APPARATUS Filed March 18, 1930. 2 Sheqts-Slieet 1 ATTORNEYS Dec. 8, 1931. E. Rou6 KA 1,835,090 AUTOMATIC FUEL FEEDING APPARATUS Filed Malrch 18, 1930 2 Sheets-Sheet 2 wmvg TOE g W Y I ATTORNEYS Patented Dec. 8, 1931 ERICHI ROUCKA, OF BLANSKO, CZECHOSLOVAKIA.

AUTOMATIC- FUEL FEEDING APPARATUS Application filed March 18, 1930, Serial No. 436,665, and in Czechoslovakia. March 30, 1929.

p This invention relates in general to apparatus, for automatically feeding fuel to furnaces which burn solid fuel upon mechanical grates, such as chain grates or travelling grates, which by their movements feed the uel.

One object of the invention is to provide apparatus of this character including a switch for controlling; the supply of power to a mo tor which actuates the mechanical grate, said switch being controlled by a temperature sensitive means responsive to the variations in temperature of the fuel bed at the fire end, or fire line, or the end of the mass of live coals at the discharge end of the grate,

whereby upon a. drop in temperature from a predetermined degree, due to movement of the fire line upon consumption of the fuel, said switch is actuated to start the motor so as to supply additional fuel.

Another object is to provide such apparatus which also includes means actuated by the motor for opening the switch, or cutting off the supply of power from said motor.

Other objects are to provide fuel feeding apparatus of the character described wherein an electric contact device is operated by the temperature sensitive means to produce electric current impulses or variations which ,close said switch for controlling the motor actuating the grate; to provide in such apparatus a contact device actuated by a means sensitive to temperature at the fire line for closing a switch controlling a motor for actuating the grate, means operated by the motor for opening said switch, in combination with means for maintaining said switch closed while said contact device is held closed by the temperature sensitive means, so that the switch is not repeatedly opened and closed during any long period in which the contact device is held closed, and to obtain other advantages and results as will be brought out bythe following description.

Referring to the accompanying drawings inwhich corresponding and like parts are designated by the same reference characters,

Figure 1 is a schematic illustration of a simple form of my invention.

Figure 2 is a schematic illustration of another form of the invention showing the switch controlling the motor in open posltlon,

and

Figure 3 is a fragmentary schematic view of the switch operating mechanism of Figure 58 2 showing the switch in closed position.

Specifically describing the embodiment of theinvention illustrated in Figure 1 of the drawings, the invention is shown, for the purposes of illustration, in connection with 60 a furnace having a known type of travelling or chain grate 1 which is actuated through worm and worm wheel gearing 2 by an electric motor 3 which is connected to the line Wires 4 of a source of electricity by wires 5 and 6'through an electric switch mechanism .which includes spaced contacts 7 and a blade noid or electromagnetic coil 11. The fuel is supplied at one end of the grate by known means, such as a hopper (not shown), and the grate travels in the direction of the arrows, the fuel being consumed upon the grate and the ashes being discharged by 7 action of gravity into an ash pit at the end of the grate opposite the fuel supply. The fire end, fire line or end of the mass of live coals upon the discharge end of the grate 1s designated 23, and the position of this fire line varies from time to time, moving toward the fuel supply end of the grate as fuel is consumed, andtowardthe discharge or ash pit end of the grate as the grate is actuated to supply additional fuel. I The coil 11 has one terminal connected to one line wire 4 and the other terminal connected to a contact point 12 mounted on a bimetallic thermostatic strip 13 arranged Within a receptacle 14 and fixedly connected at one end thereto'as at 15. The receptacle 14 is supplied with fluid, for example water, from areservoir 16 througha pipe 17, heater 18 and pipe 19. Supply of fluid to the tank 14 is controlled in known manner by a float valve 20. The heater 18 is arranged above the discharge end of the grate at a po- I sition with respect thereto corresponding to the position at which it was desired to maintain the fire line, and the fluid flowsthrough said member 18 so as to be heated by the fire at the fire line. The temperature of the fluid influences the thermostatic strip 13 in the receptacle 14 so as to move the contact point 12 into and out of contact with a screw 21 which is connected to the line wire 4 opposite that to which the coil 11 is connected. The fluid overflows from the receptacle 14 through the pipe 22 so that there is a constant flow through the receptacle.

In operation of the device, the switch 7 8 is normally open by action of gravity and the fluid passing through the member 18 is heated by the fire at the fire line 23 on the grate. Obviously the temperature of the fluid will vary according to the position of this fire line. When the fire line recedes to the right of the figure toward the supply end of the grate, the temperature of the fluid in the member 18 falls so that the thermostatic strip 14 is flexed to close the contacts 12, 21. This energizes the electromagnet 11, 10 so as to close the switch 7, 8 and start the motor 3 whereby. to actuate the grate 1 in the direction of the arrow, supply new fuel and move the fire line toward the left of the figure. The motor continues to operate so long as the contacts 12, 21 are closed. After a time the temperature of the fluid in the member 18 is designated 24, the actuating motor 25, the

fire line on the grate 26 the'fluid supply tank 27, the fluid heater 28, the receptacle for the temperature sensitive means 29, the thermo static strip 30 and the cooperating contacts 31 and 32. The contact 31 is connected to one terminal of an electromagnetic coil 33, the other terminal of which is connected at 34 to one line wire 35. The other contact 32 is connected to a spring contact strip 36 which cooperates with a contact strip 37 connected at 38 to one terminal of the motor 25. The other terminal of the motor is connected at 39 to the other line wire 35. The terminal of the motor 25 to which the switch contact 55 strip 37 is connected, is connected to the other line wire at 40 through a mercury switch 41 of known construction.

This mercury switch 41 is mounted on a lever 42 pivotally mounted intermediate its 60 ends at 43 and connected by a spring 44t0 one end of a lever 45, the other end of which is; pivoted at 46 to a fixed support. A spring 44 is connected to the lever in opposition to the spring 44. The switch 41 is held 55 in open position, as shown in Figure 2, by a rises due to the hotter fire directly beneath it This lated to the-cam that before the cam tion 51 engages the roller 55, the cam 58 moves the switch-strip 3 6 temporarily into contact detent 48 on a spring armature 49 cooperating with the electromagnetic coil 33.

In operation of the apparatus so far described, assuming the switch 41 to be open and the contacts 31, 32 separated, upon a recession of the fire line 26 toward the supply end of the grate, the temperature of the fluid in the receptacle 29 drops so that the thermostatic strip 30 is flexed to close the contacts 31, 32. The magnet 33 is then energized and attracts the armature 49 so as to remove the detent 48 from beneath the lever 45. The springs 44 and 47 then-actuate the levers 45 and 42 into the position shown in Figure 3 of the drawings so as to close the switch 41. The motor 25 is thus set in operation so as to supply more fuel to the grate and move the fire line toward the discharge end of the grate beneath the heater 28.

A cam 50 driven in any suitable manner by the motor 25 has a cani surface 51 which moves in the direction of the arrow and engages a roller 52 on the lever 45 so as to raise said lever into engagement with the detent 48. The lever 42 is prevented from following the lever 45 by a detent 53 carried by a spring strip 54, as shown in Figure 3 of the drawings. However, afterthe cam portion 51 has raised the lever 45, said cam portion engages a roller 55 on the spring strip 54 so asto disengage the detent 53 from the lever 42, whereupon the tension of the spring 44 actuates the lever 42 to open the switch. The levers 45 and 42 are maintained in proper relation by a spacing 'rod 56. If the contacts 31, 32 are still closed, the mechanism will be immediately operated as above described so as to again close the switch 41,

and the cycle will be thus repeated, closing and opening the switch 41 so long-as the contacts 31, 32 remain closed. 1

However, 'it is notdesirablethat this action be repeated, and to overcome this effect, Ihave connected the magnet 33 in circuit so that it cannot be energized as above described when the switch 41 is closed, andIhave shown an auxiliary switch mechanism which includes the contact strip 57 electrically connected to the terminal of the motor opposite the terminal to which contact strip 37 is connected, to also cooperate with the spring contact strip 36. This contact strip 36 is actuated by-a cam 58, also driven by the motor 25, for example by the same shaft 59 ,upon which the cam 50 is mounted; and this cam 58 is so repor.-

with the spring contact 57zso as to change the circuit and energize the magnet 33 ifthe c'ontacts 31, 32 are closed. Now assuming the lever 45 to have been returned tothe detent 48 as in Figure 2, and the switch lever 42 to be held by detent 53 as'in I igure 3, when the magnet 33 isenergized through the conby there is no interruption of the running of the motor 25, and repeated opening and clos ing of the circuit through the motor is avoided. When the temperature of the fluid in the receptacle 29 is raised-beyond a predetermined point, due to movement of the fire line upon feeding of additional fuel, the thermostatic strip 30 is actuated ,to open or separate the contacts 31, 32. The cam 50 re- 9 turns the lever 45 to the position shown in Figure 2 and releases the lever 42 from the 41 to close, thereby starting operation'of the motor, and a repetition of'the operation as above describedfollows.

While 1 have shown and described the invention as embodied in certain details of construction, it should be understood that this is primarily for illustrating the principles of the invention and that the invention may be utilized in many different apparatus without departin from the spirit or scope of the inventlon. gbviously other types of power operated means than the electric motor shown can be used'for actuating the grate for example motors operated by compressedair, water, steam, etc.

Having-thus described my invention, what I claim is: a

1.' A fuel feed controlling apparatus, comprising amechanical grate for feeding fuel, power operated means for actuating said grate including an electric motor, a switch for controlling supply of electricity to said motor, electromagnetic means for closing said switch, temperature sensitive means'responsive to heat at the fire line ofthe fuel bed, an electric contact device actuated by said temperature sensitive means upon a drop in temperature at the fire line below a predetermined degree to close the circuit through said electromagnet, .said electromagnet being connected in circuit so that flow,of current 2. A fuel feed controlling apparatus, com prising a mechanical grate for feeding fuel, power operated means for actuating said grate including an electric motor, a switch motor, detent means for holding sald switch in open position, an electromagnet for releasing said detent means to permit closing of the switch, a temperature sensitive means responsive to the heat at the fire line of the fuel bed, an electric contactdevice actuated by said temperatufe sensitive means upon it drop in temperature belowa'predeterinined degree to close the circuit through said electromagnet, said electromagnet andsaid contact device being connected in circuitso that the electromagnet can be actuated only when said switch is open, means operatedby said motor for opening said switch, and a second electrical contact device for temporarilyco'nnecting said electromagnet in circuit so that the latter is periodically energized while the first-mentioned contact device is closed to cooperate with said means for opening the switch for preventing opening of said switch;

3. A fuel feed controlling apparatus, comprising a mechanical grate for feeding fuel, power operated means for actuating said grate including an electric motor, an electromagnetic switch device for controlling supply of electricity to said motor, atemperatu're sensitive means responsive tp variationsjn heat at the fire line on the fuel bed, an electric' contact device actuated by said tempera- A t'ure sensitive means upon a drop in temperfor controlling supply of electricity to said 7 device so as to close said switch and start said motor, and means operated by said motor for opening said switch.

4. The apparatus setforth in claim 3 with the addition of means operated by said motor for maintaining said switch closed while said contact device remains closed.

5. The apparatus set forth in claim 3 with the addition of a second electric contact means operated by said motor and cooperating with the last-named means to maintain said switch inclosed position while the first-' named contact device remains closed.

ERIOH ROUCKA.

throughsaid contact device to said electromagnet'is interrupted by closing of said swltch, means operated by said motor for opening said switch, and a second electric contact device operated by said motor for. temporarily changing the circuit to include said electromagnet to actuate the latter while said switch is closed and cooperating with said motor operated means, for opening the switch to hold the switch closed while the first-mentioned oontactdevice is closed. 

